An increasing number of passenger vehicles manufactured today are equipped with supplemental inflatable restraints for vehicle occupants; these are commonly known as air bags. Currently, the air bag provided for the vehicle driver is mounted in a storage compartment located in the vehicle steering column. The air bag for the front seat passenger is located in a storage compartment located beneath the vehicle dash board.
It is conventional for the steering wheel hub or for the dash board to incorporate a door formed in a decorative panel. This door is normally rectangular and is separate from the surrounding panel area so that it can be swung open by the deploying air bag upon inflation.
Some of these air bag doors comprise a portion of the panel defined by a U-shaped tear seam line of weakened panel outer skin material. This outer skin is backed by a continuous layer of foam material which is foamed in situ against the outer skin in a mold. This tear seam line is fractured by the inflating air bag so that the door tears the foam and swings open about a hinge line extending between the ends of the tear line, to enable the air bag to properly deploy.
Unfortunately, this conventional process of foaming the intermediate foam layer against the skin in a mold frequently results in a sagging of the outer skin as the foam contracts slightly upon process completion. This phenomenon is caused by the inconsistent thickness of the outer skin layer. This slight depression is perceptible to vehicle occupants and presents a definite styling drawback, especially in the more expensive vehicles.
It is quite desirable to provide a decorative panel for a vehicle interior which incorporates a door covering the air bag storage compartment that has a seam line that is invisible, or visually imperceptible, to occupants of the vehicle.